Thermoelectric devices have already been proposed that use elements, called thermoelectric elements, that can be used to generate an electric current in the presence of a temperature gradient between two of their opposing faces through the phenomenon known as the Seebeck effect. These devices comprise a stack of first pipes, intended for the circulation of the exhaust gases from an engine, and second pipes, intended for the circulation of a heat-transfer fluid of a cooling circuit. The thermoelectric elements are sandwiched between the pipes so as to be subjected to a temperature gradient originating from the temperature difference between the hot exhaust gases and the cold coolant.
Such devices are particularly interesting because they make it possible to produce electricity from a conversion of the heat originating from the exhaust gases of the engine. They thus offer the possibility of reducing the fuel consumption of the vehicle by replacing, at least partially, the alternator usually provided therein in order to generate electricity from a belt driven by the crankshaft of the engine.
One drawback of the known devices is that they require a very good contact to be ensured between the thermoelectric elements and the pipes. It is thus necessary to have pipes that have a flatness and a surface finish that have an impact on the cost price of the device.
A first solution, consisting in reinforcing the contact by virtue of tie rods exerting a force on the stack of pipes, has been tested. This solution does, however, entail using pipes that do not present a risk of being crushed on one another under the effect of this force, resulting in an overconsumption of material.
Another difficulty encountered with such devices is that, on the hot pipe side, the thermoelectric elements are subjected to high temperatures whereas, on the cold pipe side, the temperatures are much lower. The requirements concerning the connection to be made between the thermoelectric elements and the pipes are therefore very different in nature on the hot pipes side and cold pipes side.